1. Field of Invention
The present invention relates to intra-oral devices for craniofacial distraction osteogenesis, and, more particularly, to an intra-oral system for both maxillary and mandibular distraction osteogenesis. The system uses computer generated, for example computed tomography (CT), information to form custom-cast, bone-traced appliances so as to attain especially strong connections to the facial bones. Stabilized platforms are attached thereto for controlling the distribution of distraction forces. Further, the CT data is used, either in the form of a medical model or a visual imaging process, to create an occlusal splint, the distractor mounting arrangement and distractor guides to manage the distraction osteogenesis endpoint. The intra-oral devices hereof overcome the vector sensitivity and distraction force dissipation of prior devices and are omnidirectional distraction devices.
2. Description of the Related Art
In the past, computerization for surgical preplanning purposes has provided stereolithographic models of the anatomic site. These are three-dimensional models constructed using digitized information from scanning devices such as laser and acoustic reflection apparatus and various types of transmission apparatus including X-ray, magnetic resonance imaging (MRI), positron emission (PET or SPECT) as well as ultrasonic radiation.
Upon data being captured by scanning a series of spaced parallel planes, the scans are combinable by computed-tomographic (CT) techniques to construct a three dimensional projection of the scan in the form of a medical model such as a stereolithographic representation. Anatomical modeling using CT-scan data is well known and is widely accepted in pre-operative planning, rehearsal of surgical procedures, and the manufacture of prosthetic devices.
U.S. Pat. No. 6,112,109 of D'urso and U.S. Patent Application Publication 2005/0133955 both describe the use of CT-scan data for constructing prosthetic devices that are custom-fit to provide a better relationship between the remaining healthy bone and the orthopedic implant.
To implement the inventor's system of orthopedic surgery several heretofore unknown devices needed to be developed. A craniofacial anatomic surgical simulator is described, infra, for mounting and working the stereolithographic model. As background to this development, Krause et al. in U.S. Pat. No. 6,701,174 comment that in the complex area of bone distraction surgery “it is difficult, if not impossible, to make accurate surgical plans based solely on a limited number of two-dimensional renderings of bone geometry. This is because of the complex and inherently three-dimensional nature of bone deformities as well as of fixator geometry. Furthermore, two-dimensional depictions of surgical plans may not accurately portray the complexities involved in accessing the target positions of the osteotome and fixator pins surrounding the operated bone. Lack of three-dimensional modeling of these geometric complexities makes it difficult to accurately mount the fixator on the patient according to the presurgical plan”.
The computer-assisted preplanning of Krause et al. made an early attempt to resolve this long-felt need through the use of a Taylor Spatial Frame—a collection of fixator struts and associated software; however, they found that the apparatus did not provide visual feedback on how the fixator frame and bone fragments should be moved over time.
As further background to the surgical simulator hereof, in the medical literature Cheung et al. In a 2007 article entitled, Vector Guidance Splint for Internal Maxillary Distraction (JL Oral Maxillofacial Surgery, pp. 1852 et seq.) reports using a Hanau Engineering Articulator, developed in the 1920's.
Taking dental articulators as the forebears of the Craniofacial Anatomic Surgical Simulator hereof leads one to view the articulator patent art starting with Hanau, U.S. Pat. No. 1,586,739 and leading patents to Tradowsky, U.S. Pat. No. 4,365,955; El Hadary, U.S. Pat. No. 5,073,109; Federici, U.S. Pat. No. 5,533,896; and Shih, U.S. Pat. No. 5,720,612. None of these devices fulfill the simulation requirements of the disclosure at hand.
The prior art for distraction osteogenesis relates back to the Ilazarov procedure in which bones were separated at an osteotomy site into two segments and gradually further separated until the new growth at the void reached the required expansion. Mechanical aids supporting the process became known as distractors and were usually screw-driven devices with each turn being translatable into an additional incremental separation. Initially, maxillofacial and mandibular distractions were performed using external frames and such frames are still in use, typically the R.E.D. II System (KLS-Martin Rigid External Distraction System, KLS Martin L. P., Jacksonville, Fla. 32250).
Later, Guerraro, U.S. Pat. No. 5,895,387 and Samchukov, U.S. Pat. No. 5,980,252 described intra-oral devices for jaw lengthening and alveolar distraction; however, the applications thereof do not include the stabilization or the maintenance of the stomatognathic system described herein.
In the intra-oral devices herein, through the use of advanced techniques enabled by computed tomographic information, by computer-aided surgical simulation, and by medical models, the surgeon is able to provide omnidirectional distraction osteogenesis with pre-established endpoints.